Telephone-exchange system



Dec. 29 1925- 1,567,280

G. A. E. LUNDELL TELEPHONE EXCHANGE S YSTEM Filed March 11, 1920 3 Sheets-Sheet 1 INVENTOR ATTORNEYS Dec. 29 1925- G. A. E. LUNDELL TELEPHONE EXCHANGE S YSTEM Filed March IL, 1920 3 Sheets-Sheet 2 N3 i m w Q w 3% NQ M m k? .u 8% 3; g im w fir 1 mmir W l fir, QP ma m \R 4N h; m @M mm M? $3 m m 3% m Q Q k 3% By ATTORNEYS Dec. 29 1925- 1,567,280

G- A. E. LUNDELL TELEPHONE EXCHANGE SYSTEM Filed March 11, 1920 3 Sheets-Sheet :5

z JwiiltirjlroR flucbu/fim ATTORNEYS Patented Dec. 29, 1925.

UNITED STATES Q 1,567,2aa

PATENT orrice.

GEORGE ALBEN E. LUNDELL, OF NEW YORK, N. Y., ASSIGNOR TO WESTERN ELECTRIC COMPANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

TELEPHONE-EXCHANGE SYSTEM.

Application filed March 11, 1920. Serial No. 364,999.

To all whom it may concern:

Be it known that I, GEORGE ALBEN E. LUNDELL, a citizen of the United States, residing at 960 Anderson Ave, New York, in the county of Bronx and State of New York, have invented certain new and useful Improvements in Telephone-Exchange Systems, of which the following is a specification.

This invention relates to automatic and semi-automatic exchange systems, and more particularly to automatic selector switches in which electromagnetically controlled devices are employed, and is adapted for use either as a selector or as a connector.

The principal object of this invention is to provide improved means whereby the activity of the brush sets of such switches is selectively controlled.

According to another object the activity of the brush sets is controlled by electromagnets equal in number to the number of differently characterized motions transmitted to the brush sets, without the necessity of providing additional electromagnets particularly for governing selection of the brush sets.

A further object resides in the provision of automatic selectors of substantial and rugged construction in which the stresses and strains set up during selection of the brush sets are carried by substantially straightand rigid parts to the rigid framework of the selector. In accordance with this object, I provide such parts of simple and improved construction, and an efficient method of forming the same.

According to a further object, the selector is inoperative if the movable member thereof becomes inadvertently displaced from its normal position, whereby incorrect selection due to such displacement is effectually prevented.

Another object relates to selecting the desired brush set by predetermining the extentof a preliminary reciprocal movement of the selector, and thus the necessity for a preliminary brush tripping zone is obviated and considerable space is saved, and the margins in the selective mechanism may be adjusted or varied without increased height or space.

Other objects and advantages will appear as the description of the invention progrosses.

By means of this invention a switch is provided by which a large number of lines may be accurately and rapidly served, and whereby any line may be reached through one of a plurality of multiple connected sets of brushes on a common shaft, each set having access to a particular group of lines only. For this purpose there is provided a panel board upon which a plurality of vertical rows of sets of stationary terminals are mounted, each row being divided into sections, and each section having a setof cooperating normally inactive movable brushes individual thereto, all the corresponding brushes of the several sets 1 having access to the same row being connected in multiple. These rows of terminals may be multiplied horizontally across the panel to be accessible to as many individual switching mechanisms as may be necessary to handle the greatest number of simultaneous calls. Each set of brushes is carried by a separate brush carrier mounted on a longitudinally movable brushv shaft common to the entire group of brush sets corresponding to a single row of stationary terminals.

In accordance with the present invention the terminals of any desired line are reached by first causing the set of brushes having access to the section containing the desired line terminal to be released to engage the stationary terminals and then causing said set to traverse the terminals in the row rnl' l the terminals of the desired line are reached.

In the embodiment of the invention herein shown, all of the brush carriers are fixed to the brush shaft to move therewith. A set of brushes is secured to each brush carrier by means of laterally flexing spring arms. Certain of these arms have cam portions arranged to be engaged by rollers of insulating material at one end of a bell crank lever whereby the brushes are forced laterally to a position to pass by the stationary terminals without engagement therewith. One of these brush controlling levers is individual to each brush set and is pivotally secured to the brush carrier immediately adjacent the brush supporting arms in such amanner that when the inwardly extending free arm of the lever occupies a horizontal position,

III

- bers the other end will project between the arms and the rollers of insulating material will engage the cam portions and will force the brushes to their retracted or inactive. position. The brushes are maintained in their inactive position, except when a connection is being made or during a c'onversatioi'i, when one set of brushes, and only one is tripped. I

A brush selecting or tripping device is provided. which is adapted to engage the brush controlling lover of a desired brush 'setto release thehrusliesand allow them,

n on movement of the brush sha' ,to traverse the stationaryterminals'of their section while the other setsof'brushes remain I arm is provided with a lug orflangeadapted to be engaged by a projection secured to the movable brush rod and ll-PO11 a "relatively short movement of the brush shaftp'to be moved by such engagement in a plane at an angle to the1directionof movement'of the rod, 1111101 135 second resting position. In'the latter position, the firstanentioned. arm intercepts the line of'travel of-the' brush con trolling lever fof'the brush setat a; point slightly below the position of the lever after such short advancement. Thns' itiw'ili be seen that after-ya relativelyshorten-ovement of the brush shaftbne upwardly extending arm is in line with the lineotz; travel of the brush controlling level" of the brush The arm beingsoinewhat shorter than the distance trav rsed by the brush; set, upon movement of'the shaft and brush sets in a reverse direction, 'the -brnsh controlling lever of one brush set will collide therewith and will be rotated and the bruslies,.-by reason of the resiliency of their supporting arms, will assume their operative position. A second lug or flange isprovided-on the upwardly extending arm of the device, and is adapted toengage projection secured to the movable brush rod in'such a -'niar-' ner thatby a relatively longer movement-of the brush'rod the arm will be moved by such engagement in a placeat :angle'to The lugs or flanges of the several tripping devices are differently positioned relative to the-normal position of the project-ions n the brush shaft, and selection of the brush set to be actuated is accomplished by controlling the extent of movement of the shaft before reversing the'direction of motion, so

as to determine the specially characterized tripping device which shall be left in its op erative resting position.

In another form of the invention a form of tripping device is provided by which the rotation of brush controlling lever takes place during the upward ll'l'OYQlIlQ'Iit ot the 'ling device therefor; Fig. is a perspective View ofone of the tripping-devices; Fig; 6 1s a diagram of a telephone exchange system,

' showing so much thereof as iszne'cessaay to a full understanding of the-invention: Fig. 7 is a side view of a' modified form oftripping device; Fip'. 8fis an'uend view otlthe operating arm of the tripping rlevi.'ce.ot Fig. 7 taken on lines 88 ofF'ig. 7,-beforethe same has been'placed in its active position;

Fig. 9 is a similar view afterwitahas been placed'in'itsactive position FigflOds a view showing the blank 7 from whichi-ione of the tripping-devices .of Fig; 5 is' fo-ined. Fig. 11 is a similar blank for use with aidifferent set of brushes; and Fig; 12indicates diagrammatically the respectivepositions-of various parts of'the mechanism at a'certain stage in the operation.

- The switch here disclosed is designed to serve a large i'iumber of lines, say 'up-to five capacity of the switch-maybe varied by providing a greater or less numberwof sections, and a corresponding number of brushes, or by arranging more or less terniinalsin each section.

To avoid needless duplication of 'pa'rts, and 1 to more clearly illustrate the-features oft-he present invention, only one selector switch is fully shown in Fig. 1.

Referring to I the drawings,- the frame of the selectormechanism of the present *invention comprises the :upright member, '15,

to which is rigidly secured-the pl-ates 16,-16.

and the plate The several banksof tornu'nals are fastened thereto in any suitable manner and are formed by electrically conducting strips of material 18, and alternate insulating strips 19 piled together in several sections as shown in Fig. 1.

Each selector switch 6 .6, see Fig. 6, coacting with such terminals, comprises a longitudinal shaft which carries a plurality of brush carriers 26, having a plate 35, securely clamped to said shattby screws 27. Each brush set includes the brushes 31, 32, S3, 34. which are carried at the ends of the laterally flexible arms 36, 37, 38, 39 respectively. These arms are rigidly secured at their other ends to the plate oi the brush carrier, and are insulated therefrom and from each other by plates of insulation. By their inherent resiliency these arms tend to force the brushes 31 and toward the brushes 33 and 3e and vice versa. Each of the arms 36 and 39 carries a block of insulating material ll by which the brushes of each pair are held in spaced relation, as shown in Fig. 3. Thus it will be seen that although normally the brushes are held away from contact with any of the stationary terminals and thus are rendered inactive, upon being tripped or released, the brush 31 will engage the terminal 42, the brushes i 2 and 33 will engage the terminal 43 and the brush 3% will engage the terminal i4, and thus will become electrically active. Each of the brush arms is provided with a soldering lug 40, and the soldering lug of the arms 37 and 38 are connected to gether electrically by means of a conductor (not shown).

The clamping plate 35 extends from the brush support 25, and is laterally oiiset adjacent to said support, as shown in Fig. 3, and is provided with the face portion 4-6 and the rebent portion 17, as shown in Fig. 2. The brush controlling lever 4-8 is rotatably mounted between the main portion of the clamping plate and the rebenl portion 47 on the pin d9.

The brush controlling lever 48 is in the shape of a bell crank, and is shown in its normal position in Fig. 2, and in this position the arms 50 thereof rest against the in nor face of the portion 46 of the plate 35. Each of the arms 50 are provided with roll ers 51 of insulating material on suitable pivotal pins, the ends of the pins being enlarged so as to retain the rollers 51. The lever 48 also comprises the extension arm 52 disposed substantially central with respect to the face 46, for a purpose which will hereinajtter appear and the resetting arm 53. The brush arms 37 and 38 are bent to form 0011- verging cam members 541- and the substantially flat parallel portions 55. In the nor mal. inactive position of the brush set the rollers 51 engage the inner faces oi these parallel pcrtions and the brushes are thus held in their retracted positions, in which they are tree of their respective stationary terminals, as shown in Fig. The brush shaft 25, 1S hollow tor the reception of the circuit wires 56, 57, which Fig. 6,-in any suitable manner. as for 025- ample, by means ot flexible wires. Mounted between the uppermost plate 16 and the plate 59 is a comn'rutator plate, shown in do tail in Fig. 6, contacting with which are the brushes such as 654i and 67 carried by the brush. rod 25.

Immediately opposite the respective ln'ush sets the plates 16 are provided with upward- 1y extending ears 66, see Fig. Loosely mounted thereon by means of the pin 6? is the U or J shaped tripping device 68. The ends of the pin 67 are flared or flattened to retain the pin in position.

The several trip fingers of a single selector switch are variously characterized, and differ from each other in respect to the length of the actuated end, so that each responds to a different degree of setting. They all are formed in the same manner, and the method of forming tripping devices in a simple, eflicient and improved manner will now be described. Such tripping devices are each formed from a blank of the form shown in Fig. 10, it being understood that the length of this blank may vary in accordance with the particular type of completed tripping device which it is desired to form. One ofthe blanks tor a differently charac terized device being shown in Fig. 11. Selection is made of the blank. from a plurality of forms, according to the device which it is desired to obtain. Such blank has the two apertures 96 and the arm 70 is bent upwardly along the line 71, 72 to form an angle of substantiall 90 degrees. The lug 73 is bent upwardly along the line T l, 75 to form an angle of substantially 90 degrees with respect to the portion 7 9. The lug 7 6 is bent upwardly along the line 77, 78 to form an angle of substantially 90 degrees with respect to the portion 79. The shank 79 carrying with it the extending lugs 73 and 76 is now bent upwardly through an angle of substantially 90 degrees, along the line 80, 81, so that the shank 7 9 is substantially parallel to the first bent arm terminating in the portion 70. The device may now be clipped in a solution to protect it from rust.

Secured to the shank 79 is the shoe or cam having the substantially flat faces 86 and 88. .This may bemounted-on either face of the upwardly extending shank 7 9. On this cam presses the spring 89 the other end of said spring being fastened to the plate 16 in any suitable manner. li hcn the tripping device 68 is rotated on its pivotal pin 67 to the right from the position illustrated in Fig. 5, the spring 89 rides on the extreme end of the flat faced portion 86 ofthe cam and the tension. of the spring 89 forces the trippingdevice back to its resting position as shown in Fig. 5. hen the tripping device 68 is moved slightly towards the left of Fig. 5, the spring 89 rides over the hump 87 of the cam 85 and the tension of the spring 89 snaps the tripping device further to the left until the spring 89 rests upon the flat faced portion 88 of the cam 85, and thus the tripping device is caused to assume a second resting position. The device is limited in its extreme motion by contact of the lower portion with the plate 16, andthroughout its movement the spring 89 engages the cam 85. It will be seen. that the tripping device 68 has two resting positions.

The brush support 25 is provided with a collar 90 for limiting the downward motion of the brush support in order that the circuit vires 56, 5'7- and 58 may not be injured or grounded by' contact with the. plates 16 of the frame, and so that no partof the brush "carriors i-nterferes with the spring 89. Each brush 'carrier is" provided with an integral z p'rojection tll, which; accordingly is longitudinally movable therewith.

The up driving 'electro-magnet 668 ispro- -'vided, andupoir actuation of this magnet,

its armature forces the'flattened portion 92 of the'brush support'25 into intimate contact-with the roller 93. The roller'93 is constantly driven in the directionindicated by the' arrow, by any suitable source of mechanical energy. Thus when themagnet 668 energized, and the manner of its energi-zation in the ope ation of setting up atelephonic conversz :ion will be subsequently set forth, the brush shaft 25 and the brushes carried thereby are-driven inan upwarddirectiOii, b(.liig retaii'ied in such displaced or off normal position by means of a pawl 95 en gaging-teeth or slots (not shown) in thefiati tened'portion 92. Thedown driving electroinagnet 698 is provided, and upon actuation -of this magnet, its armature forces the'fiatv tened portion 92 of the brush support 25'into intimate contactwith the roller 94. The roller 9% is constantly drivenin the direction 'indi'cated by the arrow in any suitable'manner. The actuation "of the magnet-698'also withdraws'the pawl 95, and thus the brush support 25* andthe brushes carried thereby are moved in downward direction.

The modification shown in Figs. 7, 8 and 9-mayalso-be formed of-substantially' flat i'PUHCiIQCl blanks and differ from the type 73 to the second plate 16.

assasso above described in regard to the structure or the operating arm. -Referring to Fig. 7,

ho arm 770 is bent upwardly and as shown tivelugs is bent so that the mean plane of the shank iii) is substantially parallel with the plane of the upwardly extending portion 770. This 'device is mounted on the pin 6. on the cars 66 immediately opposite the brush set with which it is adapted to coo erate, as will hereinafter be set forth. "l the niod ic tion of my invention shown in Figs. 7, 8, and 9 is employed, the brush controlling levers 48 are mounted on rl pin in an inverted position, instead as shown in Fig. This arrangement brings the extension arms and 53 into a position below the brush supporting flexible arms '36, 37, 38 and 39 and Fig.3 may be read as being taken looking upwardly on the line 33 of Fig. 1, so far as it shows the parts of the brush set when used with the modification of Figs. 7, 8, and 9. Secured to the shank 779- is the shoe or cam 85 having substantially flat faces whereby the pressure of the spring 89 causes the tripping device to assume either of two rest ing positions. The device is limited in its extreme motion by contact of the edges of the horizontal portion with the plate 16. In the normal resting position of this tripping device the arm 770 is positioned to one side of the line of travel of the arm 52 of the brush support, as indicated in Fig. 8. In

tance of the lugs 73 and 76- from the plate 16. Referring to Fig. 12, in which there is shown the preferred arrangement of the several types of trippingdevices in schematic diagram, the tripping device of the lowermost brushset is relatively short, as compared with that of the second tripping device from the bottom of the figure, the distance between the, lug 573 to the lower plate 16 being'less than the distance from the lug Upon advancing the brush support as stated, the several sets of brushes, togetherwith the projections 91, thereof, are advanced. The lowermost projection, associated with brush set number one, soon collides with the lower surface of the lug or o, and as SllOWil'lll the'detail draw- 111g in Figs. 5 and 7. this surface is at an angle to the vertical. Thus the lug 578 (con The lugs 776' lie responding to T3) acts as a cam, and the continued motion of the projection -forces the tripping device to the left, as viewed in F igs. 12 and 5. Simultaneously or on still further movement of the brush support the projection 91 is brought into contactual relation with lug 576 and on account of the angular setting of this lug, the tripping device is pushed back into its normal resting position. Further movement of the brush support new causes the projection 91 of the second brush carrier to contact with and move the lug 7 3 of the tripping device associated with the second set of brushes, and the second tripping device is moved to the left, that is, to its second resting position, as viewed in Fig. 5. Let it be assumed that the register setting is such as now to deenergize magnet 668 so that the brush shaft is now brought to rest. The arm 7 of the lowermost brush has been returned to its normal resting position as shown in Fig. 8, out of the line of travel, indicated therein by the dotted line. The corresponding arms of the tripping devices associated with brush sets number 3, 4: and are also in the normal resting position of Fig. 8, the projection 91 not having reached the lugs 773 of such upper tripping .devices, so that the arms 770 of such tripping devices are inactive.

To sum up, the tripping device of brush set 1 is normal, having been reset; that of brush sets 8, t and 5 are normal, not hav ing been affected; so that only the tripping device of brush set 2 is in the second resting position. It will be readily understood that upon calling other wanted subscriber lines, either brush set 1, 3, 4 or 5 may be selectively placed in the second position, and in each of such cases only one tripping device, i. e, the one selected by determination ot the extent of movement of the brush set. Such determination being under control of the register setting, as will be subsequently described in full.

In the circuit operation, the down magnet 698 is now energized. The attraction ot' the armature thereby withdraws the pawl 95 from the tooth or slotwith which it has been engaged, the member 92 is pressed against the roller 94, and the brush shaft is thus moved downwardly.

It will be noted that upon approach of the brushes to normal arms 52 of brush sets 1, 3, 4:, 5. that is of the non-selected brush set tripping devices, return along the dotted line o'F Fig. 8, to the position indicated. That of the selected brush set, in this example number 2, travels as shown in Fig. 9. The line of travel in these two figures remains unchanged of course, but the tripping device is in the off normal, active, resting position. Thus the arm 52 strikes the t'ace ot the portion 701 at an angle and moves the tripping device to the right as ance between the several parts, concerned in the described selective operation may be ma teria-lly widened as desired by merely modifying the various dimensions of the comn'iutator plate 677 and of the blanks '79, etc, without sacrificing space or requiring a taller selector, since the selective movement is reciprocal whereby the distance traversed by the brush shaft during the brush selecting operation may be the same distance to be traversed subsequently in making terminal selection. This principle is broadly new and basic in the art.

The up magnet 668 isnow energized, and the brush shaft is advanced upwardly. The outward end of arm 52 of the selected brush set, and no other, is held, and the advancement of its pivot pin 49 and carrier frame causes the rotation of the brush controlling lever 48, it being remembered that in this modification the arms 52 and 53 are below the flexible arms, 36, '37, and 38. Thus the selected set of brushes is tripped.

The rollers 51 are thus extracted from the substantially flat portions 55 of the flexible arms 37, 38 and the pairs of arms 37, 38 and 39, 40 are permitted to approach each other. At the bottom of each bank of terminals there may be provided a guide for the brushes, to guide them into the rows formed by the terminals, and upward movement of the brush shaft brings the selected set of brushes, and those only, into electrical contact with the respective sets of terminals, under control of suitable relavs and sequence switches, etc.

When release is desired, the down magnet 698 is energized, retracting the pawl 95 and pressing the member 92 into intimate con-- tact with down roller 94. When the brush shaft returns to its home position the actuated brush set is returned to its normal inoperative position by the engagcn'ient ot the lever 53, extending downwardly, with the upper face of frame member 16. This causes the insulating rollers 51 to engage the cam surfaces 54 on the arms 37, 38, thus forcing the brushes to their inactive position as shown in Fig. 3.

The arm 53 and the spring 89 are formed so that the arm 53 does not encounter the spring 89.

This modification provides a simple and eflicient means of preventing positively the liZt) inadvertent displacement of the tripping devices when the selector is at normal the arm 52 serving the double purpose of locking such trip devices (see Fig. 8) and coacting with rollers 51 to trip the selected brushes.

Returning now to the embodiment of the invention shown in Fig. 5, it will be recalled that the device 68 is adapted to take up either of'two resting positions, and each of the several tripping devices "of this embodiment are differently characterized by being differently related to the pivot pins, and thus become actuated upon different degrees of movement of the projections 91.

Having advanced the brush shait't upward- 1y, as aforesaid, a desired one of such tripping devices is retained in its active position, in the same manner as mentioned for the modification; the upwardly extending shank 79 of Fig. 5 being similar to the shank 7??) of Fig. 7.

it is now to be understood that the brush controlling lever 48 is as shown in Fig. 2. Upon energizing the down drive magnet 698 the pawl 95 is retracted and the brush rod 25 returned to the home position, and the arm 52 collides with the end of the arm '70, sa id arm 70 intercepting the line of travel of Une arm 52. 'Non-selected tripping devices have their respective arms 70 out oi such line and consequently inactive.

The selected brush controlling lever is rotated, and the downwardmovement oi the brush shaft causes the rotation of the brush controlling lever an'dthe Withdrawal of the rollers 51 accordingly permits the brushes to assume their active position. They are then advanced to the-wanted terminal.

When release is desired, the up magnet (368 is energized and the brushes are moved upwardly over the remaining terminals of the bank, (if any) and to the most fully advanced posit-imixwhich the shaft is *apable of taking.

The upwardly extending arm 53 of the tripped set of brushes engages the lower face of the plate 16 nent abo've the set o f brushes and-restores the insulating rollers 51, 51 to thesubstantially parallel' portions 55, 55 and =tlirs the brushes are reset into their norn'ral, inactive position illustrated in Thus it is seen that all the teri-ninals of the selected bank are wiped over "once for "each connection established therein, and this wiping action is effective for cleaning the terminals at frequent intervals, and thus improves the reliability of the systeiln.

The up magnet 698 is now dee'nergi'zed in a manner described below, and the down magnet 668 in turn actuateduntil ll-lIGlJ-lUSll s lflil; is inset in its'home position.

T he operation of setting up a te 'coiinec'tifon Wlll i I v be described.

1 Reserving task-4 :16; 6'0 1' .ve 'oi esents r a call slow release rel'ay ($07.

ing subscribers substation, and 602 represents a called subscribers station. A called subscribcrs station may be connected with the central oiiiceby means of line wires such as 603, 6% and upon removal of the receiver at the station 601, these line wires may become connected through any suitable form of line finder or line switch (not shown) such devices being well known in the art to which this invention appertains, to a first selector switch and sender. The circuit is thereupon closed from grounded battery G'O5,' right hand winding of relay (506, conductor-604:, substation G01, conduct-or 603, left handwinding oi relay 606 to ground. The consequent operation of relay 606 closes at its front contact a local circuit for the The calling subscriber now manipulates, in accordance with one digit of the desired i'iumbemthe calling device 608, serially connected in the circuit of his substation, in the usual manner, opening the lineintermittently and the impulses cause the intermittent release of relay 686 a corresponding number of times. Relay 50? because of its slow releasing charactei ic does HOUl'GlQZiSB during these llllpUlSGS and a circuit is closed once for each impulse caused by device as fol-l'ows'z g'round in: ture and back contact of relay 606, right hand armature and front contact of relay 607, winding of slow release relay (30:, switch arm 610, conduct-or 6 11, winding of stepping magnet 612, to grounded battery. filtepping magnet 612 is quick acting and responds to each of theimpulses by moving the rachet wheel 613 in a clock-wise direction. and the arms 614i, 615 in a similar direction. Thus the extent of movement of the ratchet wheel (313,- and arms 614:, 615 depends upon the number of impulses sent over the line. The relay 609 becomes actuated upon the initial closure of this circuit, and on-account 0i its slow releasing characteristics remains operated during the transmission of the entire set of impulses and accordingly closes at its front centa'ct a scircuit during this period for the stepping magnet (316; but upon cessation o! the series of impulses the relay releases and deenergizes in turn, the stepping magnet (316, the retraction of whose armature causes the rotation in a clockwise dircction of the ratchet wheel 17 and the associated arms 610, 618, (319. The subscriber new continues by again manipulating the calling device 608 and thereby transmits to the central office a similar set of impulses corresponding to the subsequent digit of the called subscribers number. The relay Q06 operates in the sameananner as aforesaid. and. controls intermittently a circuit from ground. armature and back contact of relay 605, armature and front contactoi f slow re- 35361361213 607, Winding of sllow release rethe conductor 6%", independent of the circuit for initially energizing this relay which included the sequence switch spring 651. The operation for relay 650 also closed the following circuit; ground, right hand armature and front contact of this relay, sequence switch spring 662, conductor 663, power magnet to grounded battery Under control (i the centering spring 664: the sequence switch is moved out of position 1 and into position 2. The relay 650 remains operatiye over the conductor 661 as aforesaid. The stepping relay 656 became operated in the fui'ulamental circuit above described and closes a circuit by way of the sequence switch spring 665 and conductor 666 through the switch arm 615 to the pair of counting-re lays corresponding to the selection to be made, in accordance with the setting of the respective register switch. Let it be assumed that the switch arms 61 and 615 have been set by the subscribers dialling operation above described into their fourth posi tion. The conductor 666 is then connected to conductor 1 and the relay 1 is accordingly energized, closing at its front contact a locking circuit for itself to ground at sequence switch spring 667, independent of the in itiatlly energizing circuit just described. Relay 1' remains, however, short circuited.

A circuit is closed from grounded battery through the up driving magnet 668, sequence switch spring 669, conductor 670, right hand front contact and armature of .relay 650 to ground. The magnet 668 is energized and presses the rod 92 into engagement with the constantly driven roll 93 and the shaft 25 is advanced in an upward direction carrying with it the brushes, upwardly.

The commutator brush 675 contacts with insulating and conducting segments oi acommutator plate 676. Upon relatively slight advancement of the brush rod 25 the projection 91 shifts the flange 73 in a horizontal direction and the lever 68 is thus forced into its oil normal resting position being held there by the pressure of the spring 89 against the flattened face of the shoe. The arm 70 now interceptsthe line of travel of the controlling lover arm The connnutator brush 675 contacts with tile lowerly disposed segment of the coin mutator bar 677 and establishes thereby a circuit from ground, sequence switch spring 676, conductor 679, commutator bar 677, commutator brush 675, conductor 655, se-

quence switch spring 656 and to the winding of relay 650, thereby establishing a short circuit for stepping relays 658. The consequent release of stepping relay 658 romoves a short circuit from around the 1'c lay one prime and causes the actuation of gization of magnet 668 and the advancement of the brush support. commutator brush 675 now breaks its contact with the lowerly disposed segment of the commutator bar 677 and the short circuit from around stepping relay 658 is broken thus causing the actuation of relay 658. A circuit is now closed from ground, armature and front contact of relay 658, sequence switch spring 665, conductor 666, switch arm 615, conductor 1, armature and front contact of counting relay one prime, to the winding of the zero counting relay and to grounded bat tery. The winding of the zero prime counting relay is however short circuited. Upon continued advancement the projection 91 engages the flange 76 and shifts the lever 68 in a horizontal direction to restore the lever to its normal resting position in which the arm 70 of the. lowermost tripping device is out of 't-he line of movement of the control lever of the lowermost set of brushes.

Simultaneously or upon still further advancement of the brush support brings the projection of the second set of brushes into engagement with the lug 73 of the second tripping device and moves the latter out of its normal inactive resting position and into its oil normal, active resting position, it being held therein by means of the spring 89 as aforesaid- The commutator brush 675 contacts with the second segment of the commutator bar 677 and establishes thereby a circuit from ground, sequence switch spring 678, conductor 679, commutator bar 677, commutator brush 675, conductor 655, sequence switch spring 656 to the winding of relay 650 and thus establishes a short circuit for the stepping relay The consequent release ot' stepping relay 65S removes the short circuit from around the 0 counting relay and causes the actuation of the last mentioned relay The fundamental circuit is thus opened, and a circuit for power magnet 635, through sequence switch spring 637 is closed at the front contact of relay 0. The sequence switch is moved under control of centering spring 636 into position 10. The counting relays release upon the opening of sequen 3 switch spring 667.

hen the commutator brush leaves the second conducting segment of the connnutator bar 677 the circuit for the relay 650 is 'l'H'UliGll and this relay retracts its armatures. The magnet 666 is dcencrgizcd, and the advancement of the brush siuaport ar rested, The brush support is retained in such advanced position by a pawl 95, A circuit is also closed fl'onr ground, right hand armature and back contact of relay 650, sequence switch spring 662, conductor 653, to the power magnet 638 and grounded battery for moving this sequence switch out of position 2. Under control of centering spring 66% the sequence switch moves into position 3.

A circuit is now closed for down magnet 698 from ground, right hand armature and back contact of relay 650, sequence switch spring 674, magnet to battery, and the actuation of this magnet withdraws the pawl 95, presses rod 92 into intimate contact with the roll 94 constantly driven in the direction indicated by the arrow. The control lever arm 52 of the second set of brushes, and no other, collides with the upwardly extending arm 70 of the second tripping device since all other such arms are free of the line of movement of the respective brush set controlling levers: that of the first brush set having been displaced but reset, and those of the third, fourth and fifth brush sets having been left undisturbed in their normal inactive resting positions.

\Vhen the brush support reaches the normal position, and upon completion of the limited reciprocal motion just described, the fundamental circuit is again closed, as decribed above, and relays 650 and 658 are operated. The actuation of relay 650 opens the circuit of down drive magnet thus discontinuing the further moven'ient of the brush support in a downward direction.

It will be seen that the construction of the arm 79 of the lever 68 is different in the several cases for the various brush sets, in that the lugs 73, 76 are variably positioned on their respective arms. The arms 70 which intercept the line of travel of the controlling lcver arms 52 of the brush sets may be equal or variable in length as desired. I have shown in the present embodiment these arms 70 as being substantially equal in the several cases. It will also be seen that these arms transmit the stresses and strains set up by the engagement of the controlling lever with the tripping lever are carried through to tie frame work of the selector switch in a simple and direct manner, and the parts are of simple and rugged construction, and the entire construction is such as to insure long life to the mechanism.

The operation of relay 658 now establishes a circuit for the counting relay to which the arm 62% is connected, this being dependent upon the extent of movement of the register switch by the calling subscriber. Assuming that four impulses had been sent in by the subscriber in setting this register, the arm is connected to the armature of counting relay 3 and a circuit is thereby closed for the operation of counting relay 3, causing the actuation of this relay. The operation of relay 65-) closes the following circuit; groiuid, right hand armature and front contact of relay 650, sequence switch spring 662, conductor 6'53, power magnet 638 to groundpd battery, movizr ig the sequence switch out of position 3 and into position 5. A circuit is now established for the driving magnet 668 as follows: grounded battery, magnet 668, sequence switch spring 669, conductor 670, right hand contact and armature of relay 650 to ground. The brush support is pressed by the actuation of the magnet 668 into intimate contact with the roller 93, and the brushes are thus again moved upwardly. During such second upward movement a circuit becomes intermittently closed from ground, sequence switch spring 678, commutator segment 680, commutator brush 654:, conductor 655, sequence switch spring 656, to short circuit the stepping relay 658 intermittently. actuated in turn, beginning with the 3 counting relay, until a sufficient number of impulses have been transmitted over the line to cause the operation of the 0 counting relay. The energization of the 0 relay opens the fundamental circuit for arresting the upward travel of the selector 646; and closes a circuit, ground, left hand armature and front contact of O relay, sequence switch spring 637, power magnet 635 to grounded battery for moving the sequence switch out of position 10and the centering spring 636 carries it to position 16. The counting relays release upon the opening of sequence switch spring 667. The opening of the fundamental circuit arrests the travel of selector 646 in the same manner as before, the release of relay 650 breaking the circuit of magnet 668. A circuit is closed, ground, right hand armature and back contact of relay 650 for moving the sequence switch out of position 5 and into position7. A circuit is now closed from ground, sequence switch spring 681,'right hand winding of relay 650, for operating thisv relay, and another ground, right hand armature and front contact of this relay, sequence switch spring 662, to power magnet 638 for moving the sequence switch out of position 7 and into position 8. The relay 650 remains actuated while the brushes, 32, 33 contact with busy lines, since busy lines have a guarding ground connected with the third wire of such lines. The circuit for retaining the relay 650 in its operated position during the test of busy lines is as follows: ground, conductor 682, brushes 32, 33 in multiple, conductor 683, sequence switch spring 684, conductor 661, left hand armature and front contact and winding of relay 650, to grounded battery. A circuit is therefore closed as follows: grounded battery, driving magnet 668, sequence switch spring 669, conductor 670, right hand front contact and armature of relay 650, to ground for actuating the driving magnet 668. The brushes are thereby advanced until the terminals of an idle line are found, and until the brushes 31, 32,33, 34: are properly sen-- The counting relays are tered thereon, this centering being controlled by the centering segments of the commutator bar 685. Having reached the terminals of an idle line, relay 650 retracts its arn'iature, there being no guarding ground on the test terminal of such a line, and deenergizes the magnet 668. A circuit is now closed from ground, sequence switch spring 660,1elt handback contact and armature of relay 656, conductor 661, sequence switch spring 68 1, conductor 683, brushes 32, 33 in multiple, test tern'iinal of the line, winding of cut otl relay 686, to grounded battery, for preventing seizure by others of this line, and for operating the cut olt' relay 686.

A circuit is closed from ground, right'hand' armature and back contact of relay 650, se quence switch spring 662, conductor 653, power magnet 638 to grounded battery, for moving the sequence switch out of position 8, and the centering spring-664 carries the sequence switch into position 1 Any suitable torm of ringing control may be employed, that shown con'iprising the ringing current source 687, the tripping relay 688, which in combination with the sequence switch, impress a calling current on the called subscribers-line for operating the bell at the called station. The response of the called subscriber, who removes his receiver, so increases the current in the winding of relay 688 as to cause its operation, and the sequence switch is moved out of position ill by virtue of a circuit through-the front contact of relay 688 and sequence switch spring 689. In position 16 conve "sational current is supplied to the called subscribers talking apparatus over the following circuit, ground, righthand winding of relay 690, sequence switch spring 657, brush 639, conductor 613, sequence switch spring 656, brush 31, the line wires and substation of the called subscriber, brush 3%, sequence switch spring 691, conductor 6 1- 5, brush 6l2,sequence switch spring 659, left hand winding of relay 690 to grounded battery.v Relay 690 operates. The

lines of the calling and called subscribers arenow conversationally joined through the condensers 692, 692.

Upon coinplctionof conversation, the respective subscribers replace their receivers, hus releasing relays 606 and 690, and releasing iii-turn the slow release relay 607, and closing the following circuits: ground, armature and back contact of relay 606, armature and back contact of relay 607, sequence switch spring 648 to power magnet 635, for moving the sequence switch out of position 16 and into position 17. A circuit is now closed from ground, sequence switch spring 672, switch arm 618, back contact of stepping magnet 616, winding of this magnet, to grounded battery, and under control of its self interrupted contact, the steering switch is moved through the various off normal positions until the arm 618 breaks the circuits to the contacts and winding of magnet 616. The arms 610, 611 and 618 are now in the normal position shown in Fig. 6 in a manner well known in the art. A circuit is now closed for operating magnet 612 in the same manner, this circuitcomprising the arm 618 at normal and arm 61s off normal, and the self interrupted contacts of the magnet 612, the consequent intermittent operation of the magnet 612 bringing the arms 614: and 615 to normal. A circuit thereupon becomes closed by way of arms 618 and 614;, both at normal and arm 623 off normal, the self interrupted contacts and winding of magnet 621, and the arms 623 and 624: are brought to normal in the same manner. A circuit is now closed from ground, sequence switch spring 672, switch arms 618, 614 and 623, all at normal, conductor 671, power magnet 635 to grounded battery, for moving this sequence switch out of position 17 and into position 1, its normal position. In passing through position 18 of this sequence switch the brushes 639, 6&0, 641, 64-2 are restored to normal in a well known manner.

The movement of the sequence switch out o'tposition 16 as aforesaid, breaks at the spring 634.- the circuit of relay 633 which accordingly retracts its armature. A circuit is now *losed from ground, armature and back contact of this relay, sequence switch spring 689, conductor 653, power magnet 638 for moving the associated sequence switch out of positions 15, 16 and into position 17.

A circuit now becomes closed, according to one embodiment of my invention, from ground, sequence switch spring 669, driving magnet 668 to grounded battery, for actuating the magnet, and the brushes are advanced to their fully advanced position at the top of the terminal bank. The restoring lever 53 at the tripped brush set collides with the lower face of the bearing plate 1.6 and the controlling means L8 are rotated to position the insulating rollers 51 between the pairs of resilient brush supporting arms, and the brush set is thus caused to resume its normal inactive position. A circuit is now closed from ground, sequence switch spring 692, commutator brush a, segment 693 closed only at the upper portion of the commutator plate 676, sequence switch spring 69 1, power magnet 638 to grounded battery, for moving the sequence switch out of position 17 and into 18, and the magnet 668 is deenergized.

A circuit is now closed from ground, right hand armature and back contact of relay 650, sequence switch spring 674, down drive magnet to grounded battery, and the actuation of this magnet withdraws the pawl 95 and presses the rod 92 into intimate contact with the roller 94, constantly driven in the direction indicated the arrow. The

lllt) brushes are thus driven in a downward direction, and when commutator brush 675 contacts with the normal segment 673, a circuit is closed, ground, sequence switch spring (392, conductor (355, commutator brush 675, segment 673, conductor 652, sequence switch spring 651, power magnet (338 to grounded battery, for movingthe sequence switch into its normal position 18, and the magnet 698 is deenergized.

The apparatus is now restored to normal, and ready for a subsequent call.

In case all lines of a sub-group are busy, the selector 64-6 is advanced to the end of the group, and commutator segment closes a circuit, ground, sequence switch spring 692, conductor 655, commutator brush 675, commutator segment 696 (closed at the end of a sub-group), sequence switch spring 694:, power magnet 638 for moving the sequence switch into position 16, in which a distinctive tone may be given the calling subscriber through the sequence switch spring 697; and when the calling subscriber replaces his receiver, the apparatus returns to normal in the same manner as for the regular call previously described.

The operation of the modification of Figs. 7, 8 and 9 is similar tothe above, and the description of the exchange apparatus can be read with it: it being only necessary to consider Fig. 2 as having the brush controlling lever l8 inverted, and Fig. 3, so far as it shows the brush structure as being taken on line l-%--13 of Fig. 1; also the numerals of Figs. 7. 8. and 9 are substituted for those of the structure of and to facilitate this the tens and units digits of the reference char. cters for like parts are the same.

lVith the modification of Figs. 7, 8, and 9 the second upward movement of the brushes may be, if desired, omitted, and if so, the sequence switch may be readily modified by on'iitting position 17 as a stopping position by omitting the centering spring 664 opening in position 17. The paragraph above beginning A circuit now becomes closed is then understood to be omitted.

Thus it will be seen that the tripping of a desired set of brushes has been accomplished by the use of switch operating magnets no more in number than the number of characters of motions: that is, one for the up motion, one for the down motion. and no more. l urthermore, the tripping devices of the respective brush sets are individual and require no interconnection, and thus may be readily carried in stock, are easily trans portable and replaceable.

Other arrangements, forms and positions, according to which the present invention may be practiced, will readily occur to those skilled in the art to which it pertains. The broad aspect of my invention is that selection of a desired brush set is accomplished by return of the shaft, so as to conserve space and improve the margins of manufacture, and I have preferred to show this inventive idea in combination with a particular form of switch, in itself an improvement; but it means whereby said brushes are caused to occupy an inoperative positionbetween said terminal rows, and a tripping device operated by said shaft whereby said brush sets may be selectively released.

2. In an automatic switch, a plurality of rows of terminals, a plurality of sets of movable brushes engageable therewith. resilient supporting means for said brushes, a shaft for moving said brushes, brush-controlling means for laterally flexing said supporting means whereby said brushes are caused to occupy an inoperative position between said terminal rows, and a plurality of variously positioned tripping devices operated by said shaft whereby said brush sets may be selectively released.

3. In an automatic switch, a shaft, a row of stationary terminals divided into a plurality of sections, a corresponding plurality of sets of brushes resiliently secured tosaid shaft, a controlling means indiridual to each set for normally retaining said lnj'ushes in inoperative position, a trip lever operated by said shaft to effect engagement with one of said controlling means whereby a prede termined brush set may be rendered active and means for moving said shaft longitudinally to cause the selected brush set to traverse the stationary terminals in itsrespective section. 4. In an automatic switch, a brush shaft, a plurality of sets of brushes resiliently secured thereto, means for causing a plurality of stages of longitudinal movement ofsaid shaft, controlling levers, one for each set, whereby the brushes thereof are normally maintained inactive, a plurality of trip fingers, one for each lever, but normally out of line of movement thereof. and means operated by said shaft whereby said fingers may be moved during the preliminary movement of said shaft to intercept the line of travel of the controlling levers of said brush sets.

5. In an automatic switch, a brush shaft, a plurality of sets of brushes resiliently secured thereto, means for causing a pluality of stages of longitudinal movement of said shaft, controlling levers, one for each set, whereby the brushes thereof are normally maintained inactive, a plurality of variously characterized trip fingers, one for each lever, but normally out of the line of movement thereof, and means operated by said shaft whereby said fingers may be moved during the preliminary movement of said shaft to intercept the line of travel of the controlling levers of said brush sets.

6. In a switch, a longitudinally movable shaft, a plurality of brushes resiliently secured thereto, means for normally retaining said brushes in inactive position, an electromagnet for advancing said shaft, a second magnet for restoring said shaft, and means operative during said restoration for selectively actuating said retaining means to release a desired brush into active position.

7. In a switch, a shaft, an electromagnet for advancing said shaft, a second electromagnet for moving said shaft in a different direction, group selecting means comprising means for rendering said selecting means active upon relatively short advancement of said shaft, means for rendering said selecting means inactive upon further advancement of said shaft, and means for actuating said selecting means upon movement of said shaft in said different direction.

8. In an automatic switch, a shaft, a plurality of sets of brushes resiliently secured thereto, means for causing a preliminary reciprocal movement of said shaft, a corresponding plurality of normally inactive trip fingers constructed to render operative the respective sets of brushes, and means operated by said shaft during the reciprocal movement of said shaft rendering said fingers active.

9. In an automatic switch, a brush shaft, a plurality of brushes resiliently secured thereto, means for causing a preliminary reciprocal movement of said shaft, controlling levers, one for each set, whereby the brushes thereof are normally maintained inactive, a plurality of variously characterized trip fingers, one for each lever, but normally out of the line of movement thereof, and means operated by said shaft whereby said fingers may be moved during the reciprocal movement of said shaft to intercept the line of travel of the controlling levers of said brush sets.

10. In a selector switch, a support,.a plurality of sets of brushes secured thereto, means for advancing said sets .of brushes, selective means whereby a selected set of brushes may be rendered active according to the degree of advancement, and means for restoring said brushes to normal upon advancement thereof to the fully advanced position of said sets of brushes.

11. In a selector switch, a support, a plurality of sets of brushes secured thereto,

means for advancing said sets of brushes, selective means whereby a selected set of brushes may be rendered active according to the degree of advancement, and means operative in the fully advanced position of said support for restoring said brushes to normal.

12. In a switch, a support, a plurality of sets of brushes resiliently secured thereto, a movable lever, means for maintaining said lever in either of two resting positions, and a stud secured to said support adapted upon movement of said support to shift said lever from one resting position to the other and (:O11tl")lli11g means normally separating the brushes of each set from each other to render the set inoperative, said controlling means positioned to engage said lever in a single one of its positions.

13. In a switch, a plurality of. sets of brushes, means for maintaining said sets of brushes normally inactive, a lever for.

actuating said maintaining means, means for forwardly moving said brushes, driving means for moving said brushes in a reverse hil'GCtlOD, and means operative upon said forward movement for rendering said lever active, said maintaining means adapted to free a desired set of brushes upon said reverse movement.

14. In a switch, a movable shaft, a plurality of brushes secured thereto, selective means for rendering said brushes active, moans operated by relatively short advancement of said shaft for rendering said selective means active, means operated by additional advancement of said shaft for rendering said selective means inactive, and means operated by restoration of said shaft to normal for rendering said selective means inactive.

15. In a selector switch, a support, a plurality of sets of brushes resiliently secured thereto, driving gear for moving said support and brushes, a controlling lever normally maintaining said brushes in inactive position, a trip lever having two resting positions adjusted in one of said positions to intercept the path of movement of said controlling lever and in the other of said positions to clear the path of movement of said controlling lever, a stud secured to said support positioned to shift said lever from one position to the other upon rela tively short movement of said support and to restore said lever to its original position upon relatively greater movement of said support.

16. In a switch, a longitudinal shaft, a plurality of sets of brushes resiliently secured thereto, controlling levers, one for each set, whereby the brushes thereof are normally maintained inactive, a plurality of variously characterized trip fingers, one for each lever, corresponding plurality of movement thereof to shift said fingers sequentially from one position to the other,

said fingers positioned in one position to:

be out of the line of movement of said controlling levers and in the other pos tion to intercept the line of movement of said levers, means for causing a preliminary re-' ciprocal movement of said shaft for setting said levers, and means for controlling the extent of said movement to predetermine the linger to be selectively positioned in its second resting position. v a f 17. In a selector switch, a plurality of sets of brushes, tripping means for selective- 1y, tripping desired sets of brushes constructed to be positively locked, if, unselected, during the, tripping operation,

18. In a selector switch, a plurality of sets of brushes, tripping devices, for tripping desired sets of brushes,a single means for locking each ofsaid tripping devices when unselected and for rendering tlie respective set of, brushes active when selected.

19. The combination with a switch having movable and stationary terminals arranged in groups, of a sequence switch, means to position said sequence.

switch to control themoven'ient of saidinovable terminalsover all the stationary terminals of a group upon each selection of said group irrespective of the electrical condition of the terminals in said group. 20. The combination with a selector switch having stationary and rec procally movable terminals arranged in groups, of a sequence switch, means to posit on sa d,

sequence switch to control the reciprocal movement of said movable terminals upon selection of a group. A

21. In a switch, a longitudinally movable shaft, a plurality of sets of brushes resili-v entlysecured thereto, means for normally retaining said brushes in inoperative position, means for advancing said shaft a'pre- 7 determined distance, means for returning said shaft a corresponding d1stance,'and a tripping device whereby said sets of brushes may be selectively tripped during such return. 22. In a switch, a longitudinally movable shaft, resilient arms uniting said brushes to, said shaft, means for laterally. displacing, the brushes of each set whereby said brushes,

are rendered inoperative, means for advanc mg said shaft a predetermined distance,

means for retracting said shaft, and a trip-- ping device whereby said brushes'may be selectively released during suchretraction,

3. In a switch, a support, a plurality of sets of brushes resiliently secured thereto, controlling means normally separating the selector brushes from each other to render the set ing said support, means for returning said support, and a tripping device for selectively actuating by such return said 0011- trollingmeans to release a desired set of iruslies. i

24. In a switch, an axially movable support, a plurality of sets of brushes secured thereto, a controlling means for each set normally holding the brushes thereof spaced to inoperative position, means for forwardly setting said support, means for retracting said support, and a tripping device whereby any desired brush set may be rendered active during such retraction.

25. In an automatic switch, a longitudinally movable: shaft, a plurality of brush sets fixed to said shafts, controlling levers for said. sets, respectively,normally holding said brushes in their inoperative position, a tripping device having a plurality of fingers positioned at, progressively inoreasy inp; distances from the normal position of said levers, and means whereby said tripping. device may be displaced during the return of said shaft to efieet operative engagement of a portion of said tripping device with the controlling lever of a predetermined brush set.

i 26. In a telephone exchange system, lines, a selector for. seizing a line, said selector comprising a support, a plurality of sets of brushesresiliently secured thereto, a movable lever, means for maintaining said lever in either of two resting positions, and a stud secured to said support adapted upon movement of said support to shift said lever from one resting position to the other, and controlling means normally separating the brushes of each set from each other to render the set inoperative, said controlling; means positioned to engage said lever in a single one of'its positions.

27. In a telephone exchange system, lines, a selector for seizing a' line, said selector comprising a movable shaft, a plurality of brushes secured thereto, selective means for rendering said brushesactive, means operated by relatively short advancement of said shaft for rendering said selecting means act1ve,means operated by additional movement of said shaft for rendering said selectivemeans inactive, and means operated by restorationof said shaft for rendering said selective means inactive. l

28. In a telephone exchange system, lines,

a selector'for seizing a line, said selector inoperativanieans for selectively advancfor maintaining said fingers'in either of two resting positions, a corresponding plurality of studs secured to said shaft adapted upon varying degrees of movement thereof to shift said fingers sequentially from one position to'the other, said fingers'positioned in one position to be out of the line of movement of said controlling levers and in the other position to intercept the line of movement of said levers, means for causing a preliminary reciprocal movement of said shaft for setting said lever, and means for controlling the extent of said movement to predetermine the finger to be selectively positioned in its" second resting position.

29. In a telephone exchange system, sub scribers lines, a selector for seizing a line, said selector comprising a longitudinally movable shaft, a plurality of sets of brushes resiliently secured thereto, means for nor mally retaining said brushes in inoperative position", means for advancing said shaft apredetermined' distance, means for returning said shaft a corresponding distance, and a tripping device whereby said sets of brushes may be selectively tripped during such return.

30; In a telephone exchange system, lines, a selector for seizing a line, said selector comprising a longitudinally movable shaft, a plurality of sets of brushes, resilient arms uniting said brushes to said shaft, means for laterally displacing the brushes of each set whereby said brushes are reiidered inopera tive, means for advancing said shaft a predetermined distance, means for retracting said shaft, and a tripping device whereby said brushes may be selectively released during such retraction. I

31. In a telephone exchange system-,- lines,

a selector for seizing a line,- said' selector comprising a support, a plurality of sets of brushes resiliently secured thereto,-v controlling means normally separating the brushes from each other to render theset inoperative, means for selectively advancing said support, means for returning said support, and a tripping device for selectively actuating by such return said controlling means to release a desiredset of brushes.

32; In atele'phone exchange system, con versational lines, a selector comprising an axially movable support, a plurality of sets of brushes secured thereto, a controlling means for each set normally holding the brushes thereof spaced to inoperative position, means for forwardly settingsaid support, mea'i'is for retracting said support, and a tripping device whereby any desired brush set may be rendered active during such-retraction.

33. An automatic switch comprising a movable shaft, a plurality of brushes resiliently secured thereto, controlling means individual to each brush for normally retaining said brushes in inoperative position, a

each controlling means, means to successivel actuate said tri in devices durin b b the advance of said brush shaft, and means to release into operative position a desired one of said brushes by the joint action of a tripping device and a controlling means as a result of motion of said brush shaft.

3l/An automatic switch comprising a movable shaft, a plurality of brushes resiliently secured thereto, controlling means individual 1:0 each brush for normally retaining said brushes in inoperative position, a tripping device" arranged to cooperate with each controlling means, means to successively actuate and restore said tripping devices during the advance of said brush shaft, and means to release into operative position desired one of said brushes by the joint action of a tripping device and a controlling meansas a result of motion of said brush shaft;

85. An automatic switch comprising a movable sh'aft, a plurality of brushes resiliently secured thereto, controlling means individual to each brush for normally retaining said brushes in inoperative position, a tripping device arranged to cooperate with each controlling means, means" to successively actuate said tripping devices during the advance ofsaid brush shaft, and means to release into operative position a desired one of said brushes by'the joint action of atripping' device and a co'ntrolling'means as a result of longitudinal motion of said brush shaft.

36: automatic switch comprising a movable shaft, a plurality of brushes resiliently secured thereto, controlling means individual tdeaclr brush for normally retaining said brushes in inoperative position, a tripping device arranged to cooperate with each controlling means, means to successively" actuate said tripping devices during the advance of said brush shaft, and means to" release into operative position a desired one of said brushes by the joint action of a tripping" device and a controlling means as a result of a plurality of movements by said brush shaft.

37. An automatic switch comprising a movable shaft, a plurality of brushes resiliently secured thereto, controlling means individual to each brush for normally retaini-ng said brushes in inoperative position, a tripping device arranged to cooperate with each controlling means, means to successively actuate said trippingdevices during the advance of said brush shaft,- and means to release into operative position a desired result of a plurality of successive longitudinal movements by said brush shaft.

38. In a telephone exchange ystem, a

selector for seizing a line, said selector comprising a support, a plurality of sets of brushes resiliently secured thereto, a movable lever, a member secured to said support arranged to move said lever from its normal position upon movement of said support, and controlling means normally separating the brushes of each set from each other to render the set inoperative, said controlling means being positioned to engage said lever in a single one of its positions.

39. In an automatic switch, the combination With a rod, a plurality of brush sets secured thereto and a row of terminals, of

means for selectively adjusting said brush 1 devices whereby the latter are successively 20 adjusted into tripping positions upon longitudinal movement of the rod, the particular brush set to be selected being determined by the stopping position of the rod.

In testimony whereof, I hereunto set my 25 hand.

GEORGE ALBEN E. LUN DELL. 

